20210127-linux swap挂载失败问题处理

问题描述：

swap无法挂载，挂载成功后，约5秒后自动umount。

环境说明：

OS:Redhat 7.6

问题现象：

查看swap没有分配大小

[root@VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           6           0           0           6
Swap:             0           0           0

问题原因：

查看自动挂载配置

[root@VM-VM-XXX-CJCOS ~]# cat /etc/fstab|grep swap
/dev/mapper/vg_srv-lv_swap swap                    swap    defaults        0 0

尝试手动挂载

[root@VM-XXX-CJCOS ~]# swapon /dev/mapper/vg_srv-lv_swap

[root@VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           6           0           0           6
Swap:             7           0           7

[root@VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           6           0           0           6
Swap:             7           0           7

[root@VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           6           0           0           6
Swap:             7           0           7

约5秒后自动umount

[root@VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           6           0           0           6
Swap:             0           0           0

[root@VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           6           0           0           6
Swap:             0           0           0

[root@VM-XXX-CJCOS ~]# swapon -a
[root@VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           6           0           0           6
Swap:             0           0           0

查看messages日志
显示和kubernetes有关

[root@VM-XXX-CJCOS ~]# tail -f /var/log/messages
......
Jan 25 18:49:11 VM-VM-XXX-CJCOS12 kubelet: I0125 18:49:11.582232   52234 client.go:104] Start docker client with request timeout=2m0s
Jan 25 18:49:11 VM-VM-XXX-CJCOS12 kubelet: F0125 18:49:11.582472   52234 server.go:273] failed to run Kubelet: failed to create kubelet: failed to get docker version: Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
Jan 25 18:49:11 VM-VM-XXX-CJCOS12 systemd: kubelet.service: main process exited, code=exited, status=255/n/a
Jan 25 18:49:11 VM-VM-XXX-CJCOS12 systemd: Unit kubelet.service entered failed state.
Jan 25 18:49:11 VM-VM-XXX-CJCOS12 systemd: kubelet.service failed.
Jan 25 18:49:16 VM-VM-XXX-CJCOS12 systemd: Configuration file /etc/systemd/system/kubelet.service is marked executable. Please remove executable permission bits. Proceeding anyway.
Jan 25 18:49:16 VM-VM-XXX-CJCOS12 systemd: Reloading.

由于是测试服务去，k8s已经不在使用，停止kubelet后，再次挂载swap

[root@VM-XXX-CJCOS ~]# systemctl stop kubelet.servic
systemctl disable kubelet.service
[root@VM-XXX-CJCOS ~]# swapon /dev/mapper/vg_srv-lv_swap

再次查看，恢复正常

[root@VM-VM-XXX-CJCOS ~]# free -g
              total        used        free      shared  buff/cache   available
Mem:              7           0           3           0           3           6
Swap:             7           0           7
[root@VM-VM-XXX-CJCOS ~]# swapon -s
Filename                Type        Size    Used    Priority
/dev/dm-1                                  partition    8388604    0    -2

###chenjuchao 2021-01-27 19:25###
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